In general, most softeners are operated at a high regeneration level for three practical reasons: 1. a softener requires fewer regenerations: 2. effluent has less hardness leakage; and 3. salt is cheap. This condition, however, results in poor regeneration efficiency and maximum salt discharge into the environment. The softener regeneration efficiency can be improved by modifications to the brine system. This includes the following strategies: 1. Reduce the salt dosage to achieve at least 3,350 gr/lb of salt and regenerate tite softener more frequently. 2. Reclaim a portion of the used saltbrine for recycle back to the softener during the next regeneration. This is only applicable to softeners that must be operated in the high salt dosage mode. 3. Capture and purify the used salt brine by chemical precipitation, settling, filtration and neutralization to achieve zero discharge. Alternatively, contract with a service provider for portable exchange softener units. In all cases, because of the inherent low-cost of salt, adopting these conservation strategies will not necessarily lower the overall cost for producing soft water. But you will be doing your part to reduce salt discharge into the environment and thereby enhance and maintain the quality of our freshwater reservoirs.

The role of impurities in the selection and application of water treatment programs is discussed. With regard to dissolved gases, oxygen is the most objectionable from the standpoint of boiler feedwater supply, since this gas is the principle cause of internal pitting-type corrosion. The boiler operating pressure influences the selection and application of an internal treatment method. Boilers operated at low pressure tolerate more sludge than is the case at higher pressures because of the higher rates of heat transfer and ratings associated with higher pressures. Deposits that form on the heat transfer surfaces cause an increase in metal temperature, and eventually lead to failure. Excess sodium phosphate can concentrate is these films, giving rise to a condition known as phosphate hide out.

Water conservation projects start by conducting a water balance study. This indicates where and how water is used in the plant. It also provides detailed information of the water quality in each system. Since cooling water applications typicaliy represent the largest demand on fresh water supplies, it's best to seek our alternative sources for cooling rower makeup. This includes Project, boiler Slowdown, and treated wastewater. Likewise, one should verify that the cooling towers are operating at maximum cycles of concentration. Increasing eye les by softening the makeup offers the benefit of operatiog at higher cycles as compared to the limitations imposed by using hard, unsoftened makeup. This improves cooling tower efficiency by minimizing the volume of breed sent to drain. Finally, cooling tower bleed can be regenerated and recycled by chemical treatment methods such as lime/soda ash softening. pH adjustment, filtration, ultrafiltration, and RO- If this proves economically or logistically unfeasible, the tower bleed can often be used "as is" for wash or scrubber water applications. Assuming that the current trend of increased demand for fresh water supplies continues (and it will), all industrial plans will be faced sooner or later with the need to reduce fresh water withdrawals, maximize water reuse, minimize wastewater generation, and conrroi costs. The technology exists for acliieving these goals by the skillful analysis, synthesis and retrofit of industrial water-using nerworks.

Achieving maximum utility and life expectancy from a water distribution system requires an understanding of the problems water can cause and the various materi als of construction that are available to minimize or eliminate these problems. Working together, corrosion and design engineers can create a water distribution system for any application that will last for 50 to 100 years.

The use of soft water makeup for cooling lower operation offers several advantages over hard water makeup. Here is a list of some advantages: • Soft water eliminates mineral scale deposits for "bare metal" clean heat transfer surfaces. • The natural carbonate/bicarbonate buffer produccsa pH in the 9.2 to 9,6 range, which renders steel and other metals more passive and less prone to corrosion. • Soft water makeup reduces fresh water withdrawals, resulting in a significant savings in water and wastewater. • Operating the tower on soft water helps control the growth o f pathogenic organisms by maintaining the pH above the amplification range (pH > 9.2). • The purchase, storage, handling and feeding of chemical scale inhibitors and/or mineral acid is eliminated since soft water is non-scaling. Overall, the use of soft water for cooling tower makeup helps protect the natural environment, saves energy, reduces operating costs and extends the useful life of plant equipment.

Cathodic protection is a corrosion control method that is only effective in controlling corrosion in metallic structures that re in contact with an electrolyte. When corrosion is occurring in an electrolytic environment, current flows. The direction of current flow is from the area of the metal that corrodes through the electrolyte to the non-corroding area of the metal. The application of cathodic protection serves to stop the flow of corrosion current. When the potential of the cathode is equal to the potential of the anode, no current will flow and corrosion stops. The galvanic mode of cathodic protection depends upon the establishment of an intentional corrosion cell in the environment such as the structure to be protected becomes the cathode of the cell. The impressed current method of cathodic protection employs a direct electric current from an external source that is forced from a ground bed of anodes, through the electrolyte, onto the structure that is to be protected.

Monitoring the operation of a reverse osmosis system is essential requirement for the minimizing problems that adversely affect water quality and reduce the useful life of the membranes. Instrumentation plays an important role in providing the system operator with a means to continuously monitor the water quality and system operating performance. Equipment manufacturers offer a wide assortment of options for outfitting the RO with the required monitoring equipment. Membrane manufacturers publish tables of temperature correction factors that are used to normalize the permeate flow back to the standard 77°F design temperature. It is also advisable to record the totalized water consumption for both the feed water and reject. The performance of media filters upstream of the RO system are also affected by flow. An increase in salt passage is one indicator of the membrane condition.